Part I: Course overview
TDDC05: Embedded Systems
• Check www.ida.liu.se/~TDDC05
Simulation and Verification
• Course roles:
– Examiner: Simin N-T
– Course assistant: Jonas Elmqvist
– Supervisor: Calin Curescu
Lecture 1: Course overview,
Introduction to SE/modelling
• Project roles:
– Consultant: Jonas Elmqvist
– Customer: Simin N-T
Simin Nadjm-Tehrani
Real-time Systems Laboratory
Department of Computer and Information Science
Embedded systems simulation and verification
Linköping university
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Embedded systems simulation and verification
Linköping university
Industrial lecture & Feedback
• Invited lecture: Friday 20/1, Tool Demo
and short overview of UML 2.0, Telelogic
– Tell me what you think about this
lecture!
– Interested in new tool lectures?
• Book Monday 6/3 for Muddy Card
evaluation!
• Feedback is welcome continuously!
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Embedded systems
A computer system that
– is part of a larger system,
– is tailor-made for a specific
application,
– is characterised by restricted
programmability by the user,
– has tight interaction with a physical
environment.
Embedded systems simulation and verification
Linköping university
This course ...
... is about development process for
complex embedded systems
• In particular: systems in which software
is a significant component
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Systems Engineering
An interdisciplinary collaborative
approach to derive, evolve, and verify a
life-cycle balanced system solution
which satisfies customer expectations
and meets public acceptability
IEEE P1220 Standard Sys. Eng. process
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Software engineering
The Printing plant
Paper rolls
• What is the difference?
Software
package
Temp_Control is
subtype Temperature
is integer range
0..100;
Sensor_Dead,
Actuator_Dead:
exception;
...
end Temp_Control;
Embedded systems simulation and verification
Linköping university
Fetch full roll!
radio
Software
receiver
LGV
Hardware
LGV Operator
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Linköping university
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Project presentation
• The description is intentionally vague and
unstructured! It is from a real company!
• Objectives:
– to follow the process of systems engineering
(according to books) and prepare the
documentation of the work as steps gets
completed
– To learn to use the tools from scratch (given
basic theoretical knowledge)
– To learn how to plan, cooperate and follow
up plans
– To practice written and oral presentation
Embedded systems simulation and verification
Linköping university
Overview
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History of the course
Why these tools?
Assume familiarity with LIPS
The teacher roles
Group formation
The student roles
– See a potential update on the web
page once the group numbers are
fixed!
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Linköping university
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Planned & unplanned time
• Role of lectures: Orientation & theory
• See web for LIPS and Ind. Lecture!
• Other occasions:
– Time with supervisor to be booked in
advance. First meeting: Friday 27/1!
– Time with consultant to be booked in
advance
– Lab hours, no teacher attendance
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Examination
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UPG part: period 1
PROJ part: period 1 and 2
Common (group) grade: G/U
Simin ”approves” Req. Spec.
Calin ”approves” time plan & project plan, and
at each meeting follows up the resource usage
and progress
• Jonas ”approves” the design
• Simin ”approves” Test/Verification docs
• Jonas corrects the logic exercises
Check deadlines on the web!
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Linköping university
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Trouble shooting
• No knocking on the doors!
• May send mails to Calin and Jonas and
expect an answer within 2 days
• Attendance to tool problems may take a
couple of days in the worst case
Practical stuff
• Limitation on printing quota!
• Password for accessing the LIPS
templates
• Group account for project
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Linköping university
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Post-analysis
• Technical content:
– The customer will add an adjustment
to the reqs. (an update) 3 weeks from
the end of the course. The postanalysis should include a reflection on
how this change affects the design
and the verification.
• Process content:
– See next slide.
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Linköping university
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Post-analysis reflection
• What did we learn? Are the goals in the course
plan accurate?
• What was specially fun about the things we
learnt?
• How we organise/plan the work if we would
start from scratch today?
• How could the course be improved by changing
the way teachers were interacting, or by a
different timing of the ingredients in the
course?
• Would we read more if more material was
selected and put on the web pages in advance?
Embedded systems simulation and verification
Linköping university
Questions?
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This lecture: Part II
• Review of basic terminology
• Orientation about major topics in the
course:
– Review of systems engineering
process models and what they are
good for
– What are models and specifications
and why do we need them?
– Overview on verification techniques
Now to Process/Modelling …
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Handout
System development process
• There are as many models as there
are companies, but the models in
the literature emphasise common
aspects
• See figure 2.4-2.6 in Blanchard &
Fabrycky
• NOTE: resemblance to software
engineering process models!
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Linköping university
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• Figure 2.4 - 2.6
• Note concepts:
– test & evaluation
– review
– analysis
Embedded systems simulation and verification
Linköping university
Why an ideal process model?
• Methodology for novices
• Focus attention on important areas
• Standardisation in large companies
• Mechanism for measuring success
• Project overview for external
organisations/individuals
(David L. Parnas)
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Process-Technique-Tool
• Each phase in the process can be
supported by one or more techniques,
e.g. Verification:
– Testing
– Inspection
– Simulation
– Formal verification
• Each method can be supported by one
or more tools e.g. Testing:
– Test case generation, unit test tools,…
Embedded systems simulation and verification
Linköping university
Verification and Validation
• Verification: to detect errors in a
verification object (design model,
program, HW-circuit) with respect to a
requirements specification
To build the system right
• Validation: to determine whether
requirements reflect ”needs of the user”
To build the right system
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V&V in development process
User reqs
System reqs
operational system
integrated system
...
Component reqs
...
Component design
implemented component
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Notation
• System validation
• System verification
Models are built either before or
after ”the thing”.
This course:
• Requirements verification, Component
verification, Potential approach for
System level verification
• Modelling!
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Linköping university
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Specifications done usually before...
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Linköping university
Requirements
• Note difference between user
requirements and system
requirements
• Many different ways to formulate
(capture) and document (specify)
the requirements
• In systems engineering important
to trace requirements
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Linköping university
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Handout
• Different types of requirements
• See Figure 3.4 in Stevens, Jackson,
Brook & Arnold
• Not all types of requirements
validated/verified systematically
Embedded systems simulation and verification
Linköping university
Models (why?)
• Prototyping (requirements capture)
• Iterative design refinement, co-design,
distribution, optimisation,
documentation
• Subgroup/subcontractor communication
• Overview (handling complexity)
• Code generation (efficient production)
• Systematic test case generation
• Certification, formal analysis
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Models (which?)
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Architectural (component)
Functional (input - output)
Behavioural (over ”time”)
Life cycle (dependability: reliability,
safety, availability, maintainability, …)
• Other (size, weight, shape, cost, ...)
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Models (How?)
Models (How?)
Language
Method
Tool
Or vice versa...
– formal/semi-formal
– general/specific
– specification type: requirements,
design, environment, ...
– purpose: verification, optimisation,
test generation, …
Model used in a process
Language
Tool
Method
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System design approach (1)
• Function-oriented
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System design approach(2)
• State-oriented
Requirements
Requirements
Functions
States
States
Functions
Architecture
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System design approach(3)
• Object-oriented
Architecture
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What does UML deliver?
• All three computational models
– State-based
– dataflow-based
– Object-based
Requirements
Objects
• With no (complete) formal semantics! /
• No mechanisms for systematic tracing of
requirements
Architecture
• Soon: UML profile for systems engineering
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Handout
• What does it look like in the real
world?
• See figure 2.1 in Shumate & Keller
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V&V methods
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In reality done using a combination of
following activities:
Testing
Inspection
Simulation
Formal verification
This course
Prototyping
Use cases (scenarios)
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Linköping university
}
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Ideal ¾Reality
Problems not deeply studied in the
course:
• Non-functional requirements
• Legacy modules
• Technological development &
interoperability issues
• Organisation, personnel resources,
professional education
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Simulation vs. Formal verification
• Simulation can demonstrate what will
happen
– Presence of the desired
• Formal verification can prove what will
not happen
– Absence of the undesired
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